2 * PCM Plug-In shared (kernel/library) code
3 * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
4 * Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
7 * This library is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Library General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27 #include <linux/slab.h>
28 #include <linux/time.h>
29 #include <linux/vmalloc.h>
30 #include <sound/core.h>
31 #include <sound/pcm.h>
32 #include <sound/pcm_params.h>
33 #include "pcm_plugin.h"
35 #define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
36 #define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
39 * because some cards might have rates "very close", we ignore
40 * all "resampling" requests within +-5%
42 static int rate_match(unsigned int src_rate
, unsigned int dst_rate
)
44 unsigned int low
= (src_rate
* 95) / 100;
45 unsigned int high
= (src_rate
* 105) / 100;
46 return dst_rate
>= low
&& dst_rate
<= high
;
49 static int snd_pcm_plugin_alloc(struct snd_pcm_plugin
*plugin
, snd_pcm_uframes_t frames
)
51 struct snd_pcm_plugin_format
*format
;
55 struct snd_pcm_plugin_channel
*c
;
57 if (plugin
->stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
58 format
= &plugin
->src_format
;
60 format
= &plugin
->dst_format
;
62 if ((width
= snd_pcm_format_physical_width(format
->format
)) < 0)
64 size
= frames
* format
->channels
* width
;
65 if (snd_BUG_ON(size
% 8))
68 if (plugin
->buf_frames
< frames
) {
70 plugin
->buf
= kvzalloc(size
, GFP_KERNEL
);
71 plugin
->buf_frames
= frames
;
74 plugin
->buf_frames
= 0;
77 c
= plugin
->buf_channels
;
78 if (plugin
->access
== SNDRV_PCM_ACCESS_RW_INTERLEAVED
) {
79 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
83 c
->area
.addr
= plugin
->buf
;
84 c
->area
.first
= channel
* width
;
85 c
->area
.step
= format
->channels
* width
;
87 } else if (plugin
->access
== SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
) {
88 if (snd_BUG_ON(size
% format
->channels
))
90 size
/= format
->channels
;
91 for (channel
= 0; channel
< format
->channels
; channel
++, c
++) {
95 c
->area
.addr
= plugin
->buf
+ (channel
* size
);
104 int snd_pcm_plug_alloc(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t frames
)
107 if (snd_BUG_ON(!snd_pcm_plug_first(plug
)))
109 if (snd_pcm_plug_stream(plug
) == SNDRV_PCM_STREAM_PLAYBACK
) {
110 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_first(plug
);
111 while (plugin
->next
) {
112 if (plugin
->dst_frames
)
113 frames
= plugin
->dst_frames(plugin
, frames
);
114 if ((snd_pcm_sframes_t
)frames
<= 0)
116 plugin
= plugin
->next
;
117 err
= snd_pcm_plugin_alloc(plugin
, frames
);
122 struct snd_pcm_plugin
*plugin
= snd_pcm_plug_last(plug
);
123 while (plugin
->prev
) {
124 if (plugin
->src_frames
)
125 frames
= plugin
->src_frames(plugin
, frames
);
126 if ((snd_pcm_sframes_t
)frames
<= 0)
128 plugin
= plugin
->prev
;
129 err
= snd_pcm_plugin_alloc(plugin
, frames
);
138 snd_pcm_sframes_t
snd_pcm_plugin_client_channels(struct snd_pcm_plugin
*plugin
,
139 snd_pcm_uframes_t frames
,
140 struct snd_pcm_plugin_channel
**channels
)
142 *channels
= plugin
->buf_channels
;
146 int snd_pcm_plugin_build(struct snd_pcm_substream
*plug
,
148 struct snd_pcm_plugin_format
*src_format
,
149 struct snd_pcm_plugin_format
*dst_format
,
151 struct snd_pcm_plugin
**ret
)
153 struct snd_pcm_plugin
*plugin
;
154 unsigned int channels
;
156 if (snd_BUG_ON(!plug
))
158 if (snd_BUG_ON(!src_format
|| !dst_format
))
160 plugin
= kzalloc(sizeof(*plugin
) + extra
, GFP_KERNEL
);
165 plugin
->stream
= snd_pcm_plug_stream(plug
);
166 plugin
->access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
167 plugin
->src_format
= *src_format
;
168 plugin
->src_width
= snd_pcm_format_physical_width(src_format
->format
);
169 snd_BUG_ON(plugin
->src_width
<= 0);
170 plugin
->dst_format
= *dst_format
;
171 plugin
->dst_width
= snd_pcm_format_physical_width(dst_format
->format
);
172 snd_BUG_ON(plugin
->dst_width
<= 0);
173 if (plugin
->stream
== SNDRV_PCM_STREAM_PLAYBACK
)
174 channels
= src_format
->channels
;
176 channels
= dst_format
->channels
;
177 plugin
->buf_channels
= kcalloc(channels
, sizeof(*plugin
->buf_channels
), GFP_KERNEL
);
178 if (plugin
->buf_channels
== NULL
) {
179 snd_pcm_plugin_free(plugin
);
182 plugin
->client_channels
= snd_pcm_plugin_client_channels
;
187 int snd_pcm_plugin_free(struct snd_pcm_plugin
*plugin
)
191 if (plugin
->private_free
)
192 plugin
->private_free(plugin
);
193 kfree(plugin
->buf_channels
);
199 static snd_pcm_sframes_t
calc_dst_frames(struct snd_pcm_substream
*plug
,
200 snd_pcm_sframes_t frames
,
203 struct snd_pcm_plugin
*plugin
, *plugin_next
;
205 plugin
= snd_pcm_plug_first(plug
);
206 while (plugin
&& frames
> 0) {
207 plugin_next
= plugin
->next
;
208 if (check_size
&& plugin
->buf_frames
&&
209 frames
> plugin
->buf_frames
)
210 frames
= plugin
->buf_frames
;
211 if (plugin
->dst_frames
) {
212 frames
= plugin
->dst_frames(plugin
, frames
);
216 plugin
= plugin_next
;
221 static snd_pcm_sframes_t
calc_src_frames(struct snd_pcm_substream
*plug
,
222 snd_pcm_sframes_t frames
,
225 struct snd_pcm_plugin
*plugin
, *plugin_prev
;
227 plugin
= snd_pcm_plug_last(plug
);
228 while (plugin
&& frames
> 0) {
229 plugin_prev
= plugin
->prev
;
230 if (plugin
->src_frames
) {
231 frames
= plugin
->src_frames(plugin
, frames
);
235 if (check_size
&& plugin
->buf_frames
&&
236 frames
> plugin
->buf_frames
)
237 frames
= plugin
->buf_frames
;
238 plugin
= plugin_prev
;
243 snd_pcm_sframes_t
snd_pcm_plug_client_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t drv_frames
)
245 if (snd_BUG_ON(!plug
))
247 switch (snd_pcm_plug_stream(plug
)) {
248 case SNDRV_PCM_STREAM_PLAYBACK
:
249 return calc_src_frames(plug
, drv_frames
, false);
250 case SNDRV_PCM_STREAM_CAPTURE
:
251 return calc_dst_frames(plug
, drv_frames
, false);
258 snd_pcm_sframes_t
snd_pcm_plug_slave_size(struct snd_pcm_substream
*plug
, snd_pcm_uframes_t clt_frames
)
260 if (snd_BUG_ON(!plug
))
262 switch (snd_pcm_plug_stream(plug
)) {
263 case SNDRV_PCM_STREAM_PLAYBACK
:
264 return calc_dst_frames(plug
, clt_frames
, false);
265 case SNDRV_PCM_STREAM_CAPTURE
:
266 return calc_src_frames(plug
, clt_frames
, false);
273 static int snd_pcm_plug_formats(const struct snd_mask
*mask
,
274 snd_pcm_format_t format
)
276 struct snd_mask formats
= *mask
;
277 u64 linfmts
= (SNDRV_PCM_FMTBIT_U8
| SNDRV_PCM_FMTBIT_S8
|
278 SNDRV_PCM_FMTBIT_U16_LE
| SNDRV_PCM_FMTBIT_S16_LE
|
279 SNDRV_PCM_FMTBIT_U16_BE
| SNDRV_PCM_FMTBIT_S16_BE
|
280 SNDRV_PCM_FMTBIT_U24_LE
| SNDRV_PCM_FMTBIT_S24_LE
|
281 SNDRV_PCM_FMTBIT_U24_BE
| SNDRV_PCM_FMTBIT_S24_BE
|
282 SNDRV_PCM_FMTBIT_U24_3LE
| SNDRV_PCM_FMTBIT_S24_3LE
|
283 SNDRV_PCM_FMTBIT_U24_3BE
| SNDRV_PCM_FMTBIT_S24_3BE
|
284 SNDRV_PCM_FMTBIT_U32_LE
| SNDRV_PCM_FMTBIT_S32_LE
|
285 SNDRV_PCM_FMTBIT_U32_BE
| SNDRV_PCM_FMTBIT_S32_BE
);
286 snd_mask_set(&formats
, (__force
int)SNDRV_PCM_FORMAT_MU_LAW
);
288 if (formats
.bits
[0] & lower_32_bits(linfmts
))
289 formats
.bits
[0] |= lower_32_bits(linfmts
);
290 if (formats
.bits
[1] & upper_32_bits(linfmts
))
291 formats
.bits
[1] |= upper_32_bits(linfmts
);
292 return snd_mask_test(&formats
, (__force
int)format
);
295 static const snd_pcm_format_t preferred_formats
[] = {
296 SNDRV_PCM_FORMAT_S16_LE
,
297 SNDRV_PCM_FORMAT_S16_BE
,
298 SNDRV_PCM_FORMAT_U16_LE
,
299 SNDRV_PCM_FORMAT_U16_BE
,
300 SNDRV_PCM_FORMAT_S24_3LE
,
301 SNDRV_PCM_FORMAT_S24_3BE
,
302 SNDRV_PCM_FORMAT_U24_3LE
,
303 SNDRV_PCM_FORMAT_U24_3BE
,
304 SNDRV_PCM_FORMAT_S24_LE
,
305 SNDRV_PCM_FORMAT_S24_BE
,
306 SNDRV_PCM_FORMAT_U24_LE
,
307 SNDRV_PCM_FORMAT_U24_BE
,
308 SNDRV_PCM_FORMAT_S32_LE
,
309 SNDRV_PCM_FORMAT_S32_BE
,
310 SNDRV_PCM_FORMAT_U32_LE
,
311 SNDRV_PCM_FORMAT_U32_BE
,
316 snd_pcm_format_t
snd_pcm_plug_slave_format(snd_pcm_format_t format
,
317 const struct snd_mask
*format_mask
)
321 if (snd_mask_test(format_mask
, (__force
int)format
))
323 if (!snd_pcm_plug_formats(format_mask
, format
))
324 return (__force snd_pcm_format_t
)-EINVAL
;
325 if (snd_pcm_format_linear(format
)) {
326 unsigned int width
= snd_pcm_format_width(format
);
327 int unsignd
= snd_pcm_format_unsigned(format
) > 0;
328 int big
= snd_pcm_format_big_endian(format
) > 0;
329 unsigned int badness
, best
= -1;
330 snd_pcm_format_t best_format
= (__force snd_pcm_format_t
)-1;
331 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); i
++) {
332 snd_pcm_format_t f
= preferred_formats
[i
];
334 if (!snd_mask_test(format_mask
, (__force
int)f
))
336 w
= snd_pcm_format_width(f
);
340 badness
= width
- w
+ 32;
341 badness
+= snd_pcm_format_unsigned(f
) != unsignd
;
342 badness
+= snd_pcm_format_big_endian(f
) != big
;
343 if (badness
< best
) {
348 if ((__force
int)best_format
>= 0)
351 return (__force snd_pcm_format_t
)-EINVAL
;
354 case SNDRV_PCM_FORMAT_MU_LAW
:
355 for (i
= 0; i
< ARRAY_SIZE(preferred_formats
); ++i
) {
356 snd_pcm_format_t format1
= preferred_formats
[i
];
357 if (snd_mask_test(format_mask
, (__force
int)format1
))
362 return (__force snd_pcm_format_t
)-EINVAL
;
367 int snd_pcm_plug_format_plugins(struct snd_pcm_substream
*plug
,
368 struct snd_pcm_hw_params
*params
,
369 struct snd_pcm_hw_params
*slave_params
)
371 struct snd_pcm_plugin_format tmpformat
;
372 struct snd_pcm_plugin_format dstformat
;
373 struct snd_pcm_plugin_format srcformat
;
374 snd_pcm_access_t src_access
, dst_access
;
375 struct snd_pcm_plugin
*plugin
= NULL
;
377 int stream
= snd_pcm_plug_stream(plug
);
378 int slave_interleaved
= (params_channels(slave_params
) == 1 ||
379 params_access(slave_params
) == SNDRV_PCM_ACCESS_RW_INTERLEAVED
);
382 case SNDRV_PCM_STREAM_PLAYBACK
:
383 dstformat
.format
= params_format(slave_params
);
384 dstformat
.rate
= params_rate(slave_params
);
385 dstformat
.channels
= params_channels(slave_params
);
386 srcformat
.format
= params_format(params
);
387 srcformat
.rate
= params_rate(params
);
388 srcformat
.channels
= params_channels(params
);
389 src_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
390 dst_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
391 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
393 case SNDRV_PCM_STREAM_CAPTURE
:
394 dstformat
.format
= params_format(params
);
395 dstformat
.rate
= params_rate(params
);
396 dstformat
.channels
= params_channels(params
);
397 srcformat
.format
= params_format(slave_params
);
398 srcformat
.rate
= params_rate(slave_params
);
399 srcformat
.channels
= params_channels(slave_params
);
400 src_access
= (slave_interleaved
? SNDRV_PCM_ACCESS_RW_INTERLEAVED
:
401 SNDRV_PCM_ACCESS_RW_NONINTERLEAVED
);
402 dst_access
= SNDRV_PCM_ACCESS_RW_INTERLEAVED
;
408 tmpformat
= srcformat
;
410 pdprintf("srcformat: format=%i, rate=%i, channels=%i\n",
414 pdprintf("dstformat: format=%i, rate=%i, channels=%i\n",
419 /* Format change (linearization) */
420 if (! rate_match(srcformat
.rate
, dstformat
.rate
) &&
421 ! snd_pcm_format_linear(srcformat
.format
)) {
422 if (srcformat
.format
!= SNDRV_PCM_FORMAT_MU_LAW
)
424 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
425 err
= snd_pcm_plugin_build_mulaw(plug
,
426 &srcformat
, &tmpformat
,
430 err
= snd_pcm_plugin_append(plugin
);
432 snd_pcm_plugin_free(plugin
);
435 srcformat
= tmpformat
;
436 src_access
= dst_access
;
439 /* channels reduction */
440 if (srcformat
.channels
> dstformat
.channels
) {
441 tmpformat
.channels
= dstformat
.channels
;
442 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
443 pdprintf("channels reduction: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
446 err
= snd_pcm_plugin_append(plugin
);
448 snd_pcm_plugin_free(plugin
);
451 srcformat
= tmpformat
;
452 src_access
= dst_access
;
455 /* rate resampling */
456 if (!rate_match(srcformat
.rate
, dstformat
.rate
)) {
457 if (srcformat
.format
!= SNDRV_PCM_FORMAT_S16
) {
458 /* convert to S16 for resampling */
459 tmpformat
.format
= SNDRV_PCM_FORMAT_S16
;
460 err
= snd_pcm_plugin_build_linear(plug
,
461 &srcformat
, &tmpformat
,
465 err
= snd_pcm_plugin_append(plugin
);
467 snd_pcm_plugin_free(plugin
);
470 srcformat
= tmpformat
;
471 src_access
= dst_access
;
473 tmpformat
.rate
= dstformat
.rate
;
474 err
= snd_pcm_plugin_build_rate(plug
,
475 &srcformat
, &tmpformat
,
477 pdprintf("rate down resampling: src=%i, dst=%i returns %i\n", srcformat
.rate
, tmpformat
.rate
, err
);
480 err
= snd_pcm_plugin_append(plugin
);
482 snd_pcm_plugin_free(plugin
);
485 srcformat
= tmpformat
;
486 src_access
= dst_access
;
490 if (srcformat
.format
!= dstformat
.format
) {
491 tmpformat
.format
= dstformat
.format
;
492 if (srcformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
||
493 tmpformat
.format
== SNDRV_PCM_FORMAT_MU_LAW
) {
494 err
= snd_pcm_plugin_build_mulaw(plug
,
495 &srcformat
, &tmpformat
,
498 else if (snd_pcm_format_linear(srcformat
.format
) &&
499 snd_pcm_format_linear(tmpformat
.format
)) {
500 err
= snd_pcm_plugin_build_linear(plug
,
501 &srcformat
, &tmpformat
,
506 pdprintf("format change: src=%i, dst=%i returns %i\n", srcformat
.format
, tmpformat
.format
, err
);
509 err
= snd_pcm_plugin_append(plugin
);
511 snd_pcm_plugin_free(plugin
);
514 srcformat
= tmpformat
;
515 src_access
= dst_access
;
518 /* channels extension */
519 if (srcformat
.channels
< dstformat
.channels
) {
520 tmpformat
.channels
= dstformat
.channels
;
521 err
= snd_pcm_plugin_build_route(plug
, &srcformat
, &tmpformat
, &plugin
);
522 pdprintf("channels extension: src=%i, dst=%i returns %i\n", srcformat
.channels
, tmpformat
.channels
, err
);
525 err
= snd_pcm_plugin_append(plugin
);
527 snd_pcm_plugin_free(plugin
);
530 srcformat
= tmpformat
;
531 src_access
= dst_access
;
535 if (src_access
!= dst_access
) {
536 err
= snd_pcm_plugin_build_copy(plug
,
540 pdprintf("interleave change (copy: returns %i)\n", err
);
543 err
= snd_pcm_plugin_append(plugin
);
545 snd_pcm_plugin_free(plugin
);
553 snd_pcm_sframes_t
snd_pcm_plug_client_channels_buf(struct snd_pcm_substream
*plug
,
555 snd_pcm_uframes_t count
,
556 struct snd_pcm_plugin_channel
**channels
)
558 struct snd_pcm_plugin
*plugin
;
559 struct snd_pcm_plugin_channel
*v
;
560 struct snd_pcm_plugin_format
*format
;
561 int width
, nchannels
, channel
;
562 int stream
= snd_pcm_plug_stream(plug
);
564 if (snd_BUG_ON(!buf
))
566 if (stream
== SNDRV_PCM_STREAM_PLAYBACK
) {
567 plugin
= snd_pcm_plug_first(plug
);
568 format
= &plugin
->src_format
;
570 plugin
= snd_pcm_plug_last(plug
);
571 format
= &plugin
->dst_format
;
573 v
= plugin
->buf_channels
;
575 if ((width
= snd_pcm_format_physical_width(format
->format
)) < 0)
577 nchannels
= format
->channels
;
578 if (snd_BUG_ON(plugin
->access
!= SNDRV_PCM_ACCESS_RW_INTERLEAVED
&&
579 format
->channels
> 1))
581 for (channel
= 0; channel
< nchannels
; channel
++, v
++) {
584 v
->wanted
= (stream
== SNDRV_PCM_STREAM_CAPTURE
);
586 v
->area
.first
= channel
* width
;
587 v
->area
.step
= nchannels
* width
;
592 snd_pcm_sframes_t
snd_pcm_plug_write_transfer(struct snd_pcm_substream
*plug
, struct snd_pcm_plugin_channel
*src_channels
, snd_pcm_uframes_t size
)
594 struct snd_pcm_plugin
*plugin
, *next
;
595 struct snd_pcm_plugin_channel
*dst_channels
;
597 snd_pcm_sframes_t frames
= size
;
599 plugin
= snd_pcm_plug_first(plug
);
603 if ((next
= plugin
->next
) != NULL
) {
604 snd_pcm_sframes_t frames1
= frames
;
605 if (plugin
->dst_frames
) {
606 frames1
= plugin
->dst_frames(plugin
, frames
);
610 if ((err
= next
->client_channels(next
, frames1
, &dst_channels
)) < 0) {
613 if (err
!= frames1
) {
615 if (plugin
->src_frames
) {
616 frames
= plugin
->src_frames(plugin
, frames1
);
623 pdprintf("write plugin: %s, %li\n", plugin
->name
, frames
);
624 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
626 src_channels
= dst_channels
;
629 return calc_src_frames(plug
, frames
, true);
632 snd_pcm_sframes_t
snd_pcm_plug_read_transfer(struct snd_pcm_substream
*plug
, struct snd_pcm_plugin_channel
*dst_channels_final
, snd_pcm_uframes_t size
)
634 struct snd_pcm_plugin
*plugin
, *next
;
635 struct snd_pcm_plugin_channel
*src_channels
, *dst_channels
;
636 snd_pcm_sframes_t frames
= size
;
639 frames
= calc_src_frames(plug
, frames
, true);
644 plugin
= snd_pcm_plug_first(plug
);
645 while (plugin
&& frames
> 0) {
646 if ((next
= plugin
->next
) != NULL
) {
647 if ((err
= plugin
->client_channels(plugin
, frames
, &dst_channels
)) < 0) {
652 dst_channels
= dst_channels_final
;
654 pdprintf("read plugin: %s, %li\n", plugin
->name
, frames
);
655 if ((frames
= plugin
->transfer(plugin
, src_channels
, dst_channels
, frames
)) < 0)
658 src_channels
= dst_channels
;
663 int snd_pcm_area_silence(const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
664 size_t samples
, snd_pcm_format_t format
)
666 /* FIXME: sub byte resolution and odd dst_offset */
668 unsigned int dst_step
;
670 const unsigned char *silence
;
673 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
674 width
= snd_pcm_format_physical_width(format
);
677 if (dst_area
->step
== (unsigned int) width
&& width
>= 8)
678 return snd_pcm_format_set_silence(format
, dst
, samples
);
679 silence
= snd_pcm_format_silence_64(format
);
682 dst_step
= dst_area
->step
/ 8;
685 int dstbit
= dst_area
->first
% 8;
686 int dstbit_step
= dst_area
->step
% 8;
687 while (samples
-- > 0) {
693 dstbit
+= dstbit_step
;
701 while (samples
-- > 0) {
702 memcpy(dst
, silence
, width
);
709 int snd_pcm_area_copy(const struct snd_pcm_channel_area
*src_area
, size_t src_offset
,
710 const struct snd_pcm_channel_area
*dst_area
, size_t dst_offset
,
711 size_t samples
, snd_pcm_format_t format
)
713 /* FIXME: sub byte resolution and odd dst_offset */
716 int src_step
, dst_step
;
717 src
= src_area
->addr
+ (src_area
->first
+ src_area
->step
* src_offset
) / 8;
719 return snd_pcm_area_silence(dst_area
, dst_offset
, samples
, format
);
720 dst
= dst_area
->addr
+ (dst_area
->first
+ dst_area
->step
* dst_offset
) / 8;
723 width
= snd_pcm_format_physical_width(format
);
726 if (src_area
->step
== (unsigned int) width
&&
727 dst_area
->step
== (unsigned int) width
&& width
>= 8) {
728 size_t bytes
= samples
* width
/ 8;
729 memcpy(dst
, src
, bytes
);
732 src_step
= src_area
->step
/ 8;
733 dst_step
= dst_area
->step
/ 8;
736 int srcbit
= src_area
->first
% 8;
737 int srcbit_step
= src_area
->step
% 8;
738 int dstbit
= dst_area
->first
% 8;
739 int dstbit_step
= dst_area
->step
% 8;
740 while (samples
-- > 0) {
741 unsigned char srcval
;
743 srcval
= *src
& 0x0f;
745 srcval
= (*src
& 0xf0) >> 4;
747 *dst
= (*dst
& 0xf0) | srcval
;
749 *dst
= (*dst
& 0x0f) | (srcval
<< 4);
751 srcbit
+= srcbit_step
;
757 dstbit
+= dstbit_step
;
765 while (samples
-- > 0) {
766 memcpy(dst
, src
, width
);